1. Field of the Invention
The invention relates to a method for producing a polished semiconductor wafer, comprising the following steps in the stated order:    slicing a semiconductor wafer from a rod composed of semiconductor material,    material-removal processing of at least one side of the semiconductor wafer, and    polishing of at least one side of the semiconductor wafer.
2. Background Art
A semiconductor wafer generally has a polished front side, onto which electronic devices are fabricated. Increasingly stringent requirements are being made of the flatness of the front side. In order to be able to produce the largest possible number of devices on a semiconductor wafer, the necessary flatness has to be ensured as closely as possible, right up to the edge of the front side.
Most endeavors for increasing the flatness of the side surfaces of the semiconductor wafer generally, and of the front sides specifically, concentrate consistently on steps for the material-removal processing of a semiconductor wafer which influence flatness. They include, in particular, steps such as lapping, grinding, and polishing of one or both side surfaces. In practice, at least one polishing process, implemented as single-side or double-side polishing always takes place. As illustrated by DE10302611A1, however, process steps such as etching the side surfaces can also affect flatness, in particular flatness in the edge region of the side surfaces. A semiconductor wafer is usually etched before a first polishing process in order to remove damage to the surface left by a preceding shaping process, for example as a result of grinding or lapping (or a combination of these methods) of the semiconductor wafer. The patent application cited discloses an etching method wherein the semiconductor wafer is exposed, during etching, to a flow of a liquid etchant that is guided against the margin of the semiconductor wafer. In order to obtain the flattest possible side surfaces of the semiconductor wafer up to the outermost edge during the etching process, the margin of the semiconductor wafer is shielded against the flowing etchant by means of a special shield during etching. Side surfaces of the semiconductor wafers that are as flat as possible up to the outermost edge before polishing are regarded as a prerequisite for polished semiconductor wafers also having a very good geometry in the edge region. However, it has been found that the geometry in the edge region is still in need of improvement even when the process of DE10302611A1 is employed.